Water heater leaking: what to do first

Shut off power, gas and water

A. O. Smith says to cut power and water before anything else (A. O. Smith):

• Electric: switch off the breaker labeled water heater, or the main breaker if you can't tell which one.
• Gas: turn the gas shut-off valve on the pipe leading to the burner perpendicular to the pipe. Leave immediately and call the gas utility if you smell gas.
• Water: close the cold water valve on the pipe entering the top of the tank. If there isn't one, use the main shut-off.

Don't reach for a breaker while standing in water. Ready.gov says not to check the electrical system if you are wet or standing in water (Ready.gov).

Where is it leaking?

• Relief valve on the side or top: A. O. Smith says a dripping temperature and pressure relief valve means the valve failed or the temperature is set too high (A. O. Smith). Its technical bulletin adds that occasional weeping can come from pressure building in a closed system, called thermal expansion (A. O. Smith).
• Drain valve near the bottom: can leak from worn washers or loose connections and may need tightening or replacement (A. O. Smith).
• Fittings at the top: loose inlet or outlet connections can be tightened, but corroded fittings need professional replacement (A. O. Smith).
• Bottom of the tank: A. O. Smith says a leak from the base means corrosion has eaten through the steel, and the heater needs to be replaced (A. O. Smith).

Repair or replace?

Valve and fitting leaks are usually repairs. A leak from the tank body, or seeping where a fitting is welded to the tank, means replacement; A. O. Smith's bulletin says those welded fittings are not repairable (A. O. Smith). In Atlanta, the city's plumbing permit form lists replacing a water heater as work that needs a plumbing permit (City of Atlanta).

If water spread

The EPA says to dry water-damaged areas within 24 to 48 hours to prevent mold growth (EPA). See water heater leak water damage on 404 Water Damage for drying and cleanup.

Common questions

Can I keep using it if it's only dripping from the relief valve?

The relief valve is a safety device, so don't cap or plug it. Have a plumber find out why it's opening.

Is the relief valve discharging a lot of hot water?

A. O. Smith's bulletin says a large, sudden release of hot water from the relief valve points to a malfunctioning thermostat (A. O. Smith). Turn the heater off and call a plumber.